Studying the relative motions of planets Disaster and business continuity planning Deforestation Development of public infrastructure facilities. However it is not used for studying the relative motions on planets. Azimuth Declination Sidereal angle Hour angle.
Concept- Declination circle: A great circle passing through the celestial body and the poles is known as declination circle. Hour circle: Projections of the meridians or longitudinal circles in infinite numbers to intersections with the celestial sphere are called hour circles. Hour angle H.
Answer Detailed Solution Below Option 4 : 4 satellites. Explanation: In Cartesian coordinate system of space and time, we have four variables — x, y, z three space variables and t one time variable.
Explanation: Nadir point: The imaginary point at which it appears to intersect downward in the celestial sphere is known as Nadir. Zenith: If a plumb line through an observer is extended upward, the imaginary point at which it appears to intersect the celestial sphere is known as Zenith. Pole: If the axis of rotation of the earth is imagined to be extended infinitely in both directions, the points at which it meets the celestial sphere are known as poles. The point of intersection in the northern hemisphere is known as the north celestial pole and that in the southern hemisphere as the south celestial pole.
Celestial point: An imaginary sphere of infinite radius with the earth at its center and other celestial bodies studded on its inside surface is known as the celestial sphere. Scanning Framing Electromagnetic spectrum All of the above.
Imaging sensor systems are of two types: Framing systems and Scanning systems. These include imagers like photographic film cameras and return beam vide A scanning system employs a single detector with a narrow field of view that is swept across the terrain to produce an image. Temporal resolution Radiometric resolution Spatial resolution Spectral resolution.
Concept :- 1. Spatial Resolution:- Measurement of the minimum distance between two objects that will allow them to differentiate from one another in an image. Spatial resolution of the sensor refers to the size of the smallest possible feature that can be detected. Spatial resolution is a measure of smallest object that can be resolved by the sensor, or the size of area on the ground represented by each pixel.
Pixel size is used to determine resolution quality. Spectral Resolution:- Spectral resolution describes the ability of a sensor to define fine wavelength intervals. The finer the spectral resolution, the narrower the wavelength range for a particular channel or band. Spectral resolution refers to the specific wavelength intervals in electromagnetic spectrum that a sensor can record.
Narrow bands have higher spectral resolution. Radiometric Resolution:- The radiometric resolution of an imaging system describes its ability to discriminate very slight differences in energy.
The finer the radiometric resolution of a sensor, the more sensitive it is to detect small differences in reflected or emitted energy. It refers to the sensitivity of sensor to incoming radiance.
Temporal Resolution:- Each satellite has its own unique revisit schedule for obtaining image of a particular area. The frequency at which the sensor revisits an area is known as temporal resolution. For example, if a satellite images the same area every 10 days, then its temporal resolution would be 10 days.
Temporal resolution is an important factor to consider in change detection studies i. Hence, temporal resolution is the amount of time taken by sensor to return to a previously recorded location. Explanation: i Cartographic generalization , or map generalization, includes all changes in a map that are made when one derives a smaller-scale map from a larger-scale map or map data or vice versa. Slotted antenna Microstrip antenna Parabolic antenna Horn antenna. Explanation: 1.
A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam.
Selected points in a region Specified areas attributes of all pixels colours of selected places. Answer Detailed Solution Below Option 4 : colours of selected places. Concept: In a simple raster data structure the geographical entities are stored in a matrix of rectangular cells. The simplest way of encoding a raster data into computers can be understood as follows: Entity model: It represents the whole raster data. Pixel values: The pixel value for the full image is shown.
File structure: It demonstrates the method of coding raster data. Concept: GIS stands for the geographic information system. S has following components 1. Hard ware computer 2. Software 3. Data management 4. End User and 5. Methods The global positioning system GPS is a space based satellite navigation system that provides location and time information in all weather, anywhere or near the earth.
Answer Detailed Solution Below Option 4 : 2, 3 and 4 only. The following table gives information regarding the Global Positioning System. Answer Detailed Solution Below Option 2 : 36, km. Answer Detailed Solution Below Option 1 : a , b , c and d. Concept- All remote sensing images are subject to geometric distortions, depending on the manner in which the data is acquired.
They include the following- The perspective of the sensor optics. The motion and orientation of the scanning system. The stability of the platform. The altitude and velocity of platform. The terrain relief- The distortion exhibited here involves relief displacement, similar to aerial photographs, but in only one direction parallel to the direction of scan.
The curvature and rotation of earth- The eastward rotation of the Earth, during a satellite orbit causes the sweep of scanning systems to cover an area slightly to the west of each previous scan. So here all the reasons are correct. So the correct option will be A. Spherical error Spherical deficiency Spherical excess Spherical misclosure. Explanation The theodolite measures horizontal angles in the horizontal plane, but when the area becomes large , such as in the case of primary triangulation, the curvature of the earth means that such planes in large triangles called as spherical triangles or geodetic triangles are not parallel at the apices.
Answer Detailed Solution Below Option 4 : total station. Concept: A total station, also known as electronic tachometer, is an optical instrument. Concept: Altitude: i The angle of a star or other object from the horizon is called the altitude coordinate.
Why is this the maximum? Because if a star in the north has an angle of more than 90 degrees, then it has an angle of less than 90 degrees from the south horizon. Mining induces earthquake Mild earthquake tremors Cultural legends Reservoirs induce earthquakes. Explanation: Earthquake : Earthquakes are caused by seismic waves that are generated due to a sudden movement in the earth's crust. Earthquakes may occur naturally or as a result of human activities.
Mild earthquake tremors, Tectonic earthquakes, Volcanic earthquakes generated due to natural sources of earthquakes. Mining induces earthquakes, Mild earthquake tremors, Reservoirs induce earthquakes generated due to human activities. Important Points Seismic waves or Earthquake waves: The earthquake which originates in the lithosphere propagates different seismic waves or earthquake waves.
Earthquake waves are basically of two types — Body waves Surface waves Body waves: They are generated due to the release of energy at the focus and moves in all directions traveling through the body of the earth.
There are two types of body waves- 1. Primary waves P-waves : Primary waves are the fastest body waves twice the speed of S-waves and are the first to reach during an earthquake. They are similar to sound waves, i. They travel through solid, liquid, and gaseous materials. Secondary waves S- waves : They are slower than primary waves and can pass only through solid materials. They are transverse waves in which directions of particle movement and wave propagation are perpendicular to each other.
Surface waves: When the body waves interact with surface rocks, a new set of waves is generated called surface waves. Two common surface waves are - 1. Love waves L-waves : This kind of surface wave causes horizontal shifting of the earth during an earthquake. They have much slower than body waves but are faster than Rayleigh. Confined to the surface of the crust, Love waves produce entirely horizontal motion.
Rayleigh waves R-waves : These waves follow an elliptical motion. A Rayleigh wave rolls along the ground just like a wave rolls across a lake or an ocean. Most of the shaking felt from an earthquake is due to the Rayleigh wave, which can be much larger than the other waves.
Exam Preparation Simplified Learn, practice, analyse and improve. Testbook Edu Solutions Pvt. Our Apps. These innovations have been widely used as types of sensors in remote sensing since science made a giant step ahead. Over the span of time, remote sensing technology found its applications in various spheres of human life. Farmers benefit from the types of remote sensing satellites on a daily basis. There exist two main types of remote sensing classified according to the source of signal they use to explore the object, active vs.
Active remote sensing instruments operate with their own source of emission or light, while passive ones rely on the reflected one.
Each active sensor in remote sensing directs its signal to the object and then checks the response — the received quantity. The majority of devices employ microwaves since they are relatively immune to weather conditions.
Active remote sensing techniques differ by what they transmit light or waves and what they determine e. Apart from a variety of implementations, active remote sensors basically have no restrictions as to research conditions. Active types of remote sensing systems fully function at any time of the day as they do not require sunlight, and they are relatively independent of atmospheric scatterings.
Various types of remote sensing technology find implementations both in scientific branches and far more practical industries. Data acquired with remote sensing instruments serve agriculturalists and foresters. They are critical in hard-to-reach places in marine sciences and rescue missions.
Passive sensors in remote sensing do not streamline energy of their own to the researched object or surface, unlike active ones. Passive remote sensing depends on natural energy sunrays bounced by the target. For this reason, it can be applied only with proper sunlight, otherwise there will be nothing to reflect. Passive remote sensing employs multispectral or hyperspectral sensors that measure the acquired quantity with multiple band combinations. These combinations differ by the number of channels two wavelengths and more.
The most popular passive remote sensing examples of devices are various types of radiometers or spectrometers. Among examples of passive sensors in remote sensing, Landsat definitely stands out as the most long-lasting Earth-observing mission. It monitored our planet and recorded the obtained data enabling us to analyze the way it changed within a year span. In agriculture, remote sensing utilizes the reflectance properties of vegetation, measuring them, and assessing crop health with vegetation indices.
It is possible because specific values of vegetation indices correlate with certain species at a certain growth stage. The classification of microwave sensing includes active and passive types and bases on the principle of either transmitting and receiving signals or receiving only. The differentiation lies in the wavelength. In this particular case, it varies from 1cm to 1m. Unlike shorter wavelengths, they break through almost any atmospheric conditions but heavy rains.
Their insusceptibility to aerosols enables monitoring almost in any weather and at any time. Passive microwave sensing checks microwave emissions from targets. A passive sensor like a radiometer or scanner distinguishes natural energy and records it, with the difference that its antenna detects microwaves in particular, not other, shorter waves.
The method enables specialists to understand the temperature and moisture of the target via certain correlations with the radiation quantity. The energy detected by this type of sensor is emitted, transmitted, or reflected. The method provides data for many branches like meteorology, hydrology, agriculture, ecology, oceanography.
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